paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

nolanlawson

Service Worker - offline support for the web

• Service Worker - Revolution of the Web Platform
• The Service Worker is Coming - Look Busy (vid)
• Service Workers: Dynamic Responsive Images using WebP Images
• Is Service Worker ready?

Progressive apps - high-res icon, splash screen, no URL bar, etc.

• Progressive Web Apps: Escaping Tabs Without Losing Our Soul

pburtchaell

/**
 * VH and VW units can cause issues on iOS devices: http://caniuse.com/#feat=viewport-units
 * 
 * To overcome this, create media queries that target the width, height, and orientation of iOS devices. 
 * It isn't optimal, but there is really no other way to solve the problem. In this example, I am fixing 
 * the height of element `.foo` —which is a full width and height cover image.
 *
 * iOS Resolution Quick Reference: http://www.iosres.com/
 */
 

rikschennink

const createCloudinary = (cloudName, unsignedUploadPreset) => ({
    process: (fieldName, file, metadata, load, error, progress, abort) => {

        // `fieldName` and `meta` are not used for now

        const url = `https://api.cloudinary.com/v1_1/${cloudName}/upload`;
        const xhr = new XMLHttpRequest();
        const formData = new FormData();